There are numerous piece part manufacturing situations where the dimensional characteristics of the finished part are of the utmost importance. That is, after a part has exited a manufacturing process, such as machining or forming, the dimensional characteristics imparted thereto by the process must fall within predetermined design limits, which may have a tolerance on order of several thousandths of an inch or less. When such parts are manufactured in large quantities on an automated production line basis at high piece count rates, quality assurance inspection can impose a serious bottleneck on production. Thus, it is not uncommon in such situations to only randomly check the finished parts for dimensional accuracy. In so doing, trends leading to process excursions can be detected and corrective measures instituted, if necessary.
However, for certain applications calling for absolute part dimensional integrity, quality assurance inspection of each and every finished part becomes a necessity. One such application is the spacer utilized in nuclear fuel rod assemblies or bundles. An example of such a spacer is disclosed in the commonly assigned, Matzner et al. U.S. Pat. No. 4,508,679. Thus, each spacer includes a multiplicity of conjoined tubular ferrules contained by a peripheral band, with each ferrule bore providing a passage or cell for receiving a nuclear fuel rod. The rods are centered in the ferrules between two axially spaced pairs of stops and a spring. The stops are formed as inwardly projecting dimpled or fluted wall segments of the ferrule. The height of these rod centering stops, measured from the ferrule peripheral surface to the rod engaging stop surfaces, is critical in order to achieve optimum positioning of the plural rods of a fuel bundle. Thus, the height of each stop of each ferrule must be inspected for quality assurance. Since each fuel bundle utilizes a multiplicity of these spacer ferrules, they must be manufactured on a mass production basis. Quality assurance inspection of the heights of the four stops of each ferrule prior to their assembly into a full rod bundle spacer in an expeditious manner so as not to impose a production bottleneck represents a formidable challenge.
It is accordingly an object of the present invention to provide gauging apparatus for measuring the dimensional characteristics of formed piece parts on an expedited, automated basis.
A further object is to provide automated gauging apparatus of the above character which is capable of inclusion in a piece part production line without imposing limitations on finished part output rate.
Another object is to provide automated gauging apparatus of the above-character which is capable of measuring the dimensions of a multiplicity of formed part features to a high degree of accuracy.
An additional object is to provide gauging apparatus of the above-character, wherein the feature measurements are compared against established quality assurance standards pursuant to determining whether or not each part is acceptable.
Yet another object is to provide gauging apparatus of the above characters, wherein the quality assurance inspected parts are automatically sorted into separate accepted and rejected lots.
Still another object is to provide gauging apparatus of the above-character, which is capable of rendering quality assurance decisions regarding the acceptance and rejection of each part in a rapid and reliable manner over sustained operating periods without human intervention.
Other objects of the invention will in part be obvious and in part appear hereinafter.